FAQs

Validity of BIA

Our software includes several different collections of equations (called “equation sets”) to choose from, for calculating the body composition estimates. Some of these equation sets are labeled as being specific to a certain ethnicity or body type. These equation sets use equations for estimating body fat that were either developed in a study that only evaluated people of that group or were developed in a more general study but then were specifically validated for use in that group in a follow-up study.

In general, however, most people should be just fine using one of the more general-population equation sets like NHANES-III.

That being said, please keep in mind that RJL does not provide software or equations for body composition estimates for any species other than humans.

To evaluate body composition in non-human species, you will need to find published equations that have been either developed or cross-validated for your study population and you will need to replicate the test protocol (including electrode site preparation, electrode type, and placement) used by the original researcher(s).

As we grow, our gender affects how our bones, muscles, etc grow, and how fat is distributed throughout the body. Because of this, equation sets will typically use different formulas to estimate body composition based on gender.

When entering data for a person, you should always use their biological sex / gender, regardless of which gender they currently self-identify as.